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Consider the following statements.

I. Every compact Hausdorff space is normal.
II. Every metric space is normal.

Which one of the following is correct?

  • A.Both I and II are TRUE
  • B.I is TRUE and II is FALSE
  • C.I is FALSE and II is TRUE
  • D.Both I and II are FALSE

Answer: A

Both I and II are TRUE.

I: in a compact Hausdorff space, a point and a disjoint compact (closed) set can be separated, and repeating the argument with finite subcovers separates two disjoint closed sets. So the space is normal.

II: in a metric space, disjoint closed sets \(A\) and \(B\) are separated by the open sets \(\{x : d(x, A) \lt d(x, B)\}\) and \(\{x : d(x, B) \lt d(x, A)\}\). So every metric space is normal. Options declaring either statement false are wrong.

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